Oct. 26, 2022

073 - Smoke control in shopping malls - uncommon aspects that make or break the system

073 - Smoke control in shopping malls - uncommon aspects that make or break the system

Long before I started the podcast, my bread and butter was to find clever ways to remove smoke from shopping malls. Actually, I like to believe I was pretty good at the job, given the fact some of the biggest projects in Eastern Europe successfully made their way through our office. At some point (after reading Roger Harrisons PhD thesis) I figured out there is some science in the stuff we are doing in our engineering, and that day I turned into a scientist. This idea turned into passion, and passion into quite an intense research that ended up with a PhD.

What matters in this journey is not the profits or titles I've received, but my own transformation. From someone seeking to optimize a system through improving assumptions for my analytical models and some more advanced calculation methods, to someone who appreciates the complexity of airflow in a labyrinthine mall. And some conclusions of this journey I would like to share with you. What I think are the uncommon things that make or break a smoke control system in a mall? Listen to the episode and you will find out (TL:DR - design fire, architecture, inlets, architecture and outlets :))

Here are some resources you may find useful:
- Gus Gaggliardi's list of resources mentioned in the podcast intro;
- My ResearchGate with a ton of resources on smoke control;
- The only English paper from my PhD with the summary of findings;
- I've lied, there is a second paper from my PhD summarizing why it does not matter where you place the fire in a compartment when running CFD!
- Review paper on axisymmetric plume models
- Actually, a funny story - in the end, I've written a book on smoke control in malls and it is available here (in Polish, sorry!). It is a summary of my PhD and not a guidebook as I've envisioned in 2016, but still - I guess it counts as a book :)

Wojciech Wegrzynski:

Hello, Welcome to the Fire Science Show. I'm here today. All on my own recording. The solo episodes for On some topics from my own expertise, actually. I can spoil it a little ready. We're going to talk about smoke, controlling shopping. malls And the only interesting things that happened to the smoke between the point where it's released to the point where it's extracted from the building. Um, Now am I, oh, I forgot how hard it is to recall sort of episodes of. I hope you appreciate. And like this one, Uh, because I'm here doing this. On my own. I don't have to introduce someone. So I may as well just take some of your time to. Update you on the state of the project. The fire science show podcast. So I'm very, very happy how the thing is developing. I just had a very nice month in September with, um, record amount of downloads for a thousand dollars in one month. That's that's a lot, guys. Thank you very much. For sharing the episodes and in listening to it and growing attention to the podcast. I have received some very interesting reviews and comments. They've actually pushed me into top 5% of the world's podcasts. So thank you very much for that. And, uh, I appreciate. As I said many Your reviews are paramount to the growth of the show and the way how it is perceived by algorithms. Uh, very, very thankful to you. But on top of that, I just really love to, to hear from all of you, what do you think about the podcast? What does it mean for you? How do you listen to it? I read all of them. They, they, they usually make my day. I had people, uh, telling me how the bulk has helped them come back to the work. I had mothers who listened to it while working though children. That's amazing. I had people who listened to to the podcast while running and. It's seemingly makes them run farther away because the episodes are so long, I guess now I I'm probably should Recall, even longer I never thought I will have an active part in developing someone's physical fitness. So yeah. Thanks. Thanks for that, You absolutely made my day. Um, my most favorite one, I was actually letter. a technician in the fire laboratory told me that they do listen to the podcast when doing cone calorimeter tests. And that inspired them to, actually pursue a career in fire safety, engineering, and degree, while That's amazing. I got your back. go for it. It's it's worth it. And, uh, listening to the podcast while doing cone colorimetry that is. That is a great use of time, to be honest, learning fire science while doing fire science. So. Thank you. Thank you very much. It's very inspirational to read all of this and makes me very, very happy to hear that you're happy with the show and if you're unhappy with the show. And probably will not make me happy, but I probably should know that. So also you can tell me. In the recent time, I have also been connecting to some other I've met Kevin Sofen from Smart Firefighting, a great guy. Is doing a very interesting, Panel's online. I've been to one recently. It was very interesting given. I've just met Chris Logan or Fire Sprinkler Podcast. Test. Probably the biggest fire pot, cause the RESA around. also great guidance. It seems we may be, uh, capable of doing some mutual projects together. So you'll probably hear Chris in here. You'll probably hear me in his podcast. Um, I'm very looking forward to that. I also would like to give a shout out to Fire Code Tech, Gus Gagliardi I've been in his show, multiple divers. Recently, like two months ago, I've talked about fire science show So, if you haven't heard that, it's probably interesting to hear some backs background stories of how the podcast. And I must say that Gus just published a very nice and comprehensive list of online resources for fire engineers. So I'll definitely link to that in the show You you, you should definitely check it out. And, you mentioned fire science, show us his favorite podcast area. Thanks Gus. I appreciate that. That a lot. Okay. So. As you see the public is going great. I hope you enjoy listening. I see it growing a invite. New people just sent another great batch of invites to very interesting people around. Many of them replied already. Talks are scheduled much more interesting. Content is coming your way soon. So look forward for that. And, uh, for today, I hope to provide you some interesting and beneficial content on my own. So I wanted to take you hard. To something that was very dear to my heart still is probably, um, that is design of smoke control in, in the complex buildings. Actually the story of this episode is this is quite. Uh, great funnier maybe. Um, I'm a person that's very into journaling stuff. Uh, I write in notebooks. I write notes. I. Write memos. I plan out. Pieces of research that I would like to write. And I must say helping a lot in my career To do that journaling. I recommend it to anyone to keep a track of their thoughts. Because otherwise they're lost anyway. Um, it's not the point of writing, but you also have to revisit these things. And I was recently revisiting. And old notebook from somewhere like 2016. Many many years ago where I was pursuing my PhD on smoke controlling shopping malls on the effects of architecture. The impact of architecture on smoke flow and how different arrangements of architecture can change them by. parameters of smoking exhaust systems. But then we were shortly after writing our short book and carpark ventilation for Polish And I had this memo that maybe I should write a book on smoke control in shopping malls. Because it's a complicated matter actually. It's very, very complicated matter. Uh, if you want to do a really good performance based engineering, project in the shopping mall. There is a lot of things that you have to think about. Way way beyond just having a certain value of extraction rate, uh, distributed in the mall. I mean it can get the job done. The question is, have you done the. Cheapest technology to pursue the goal. If you were four. And are there any trips that you have not thought about? And often that's, that's the case. Like both are the cases. Usually the systems are not the very optimal. If you just stake a one. Analytical methods and then calculate the extraction rate and then just, without much thought to just, just implement it. So today I would love to. Share with you some thoughts from that time. Enhanced by the next six years of experience that I've gained. So back then. I was involved in many smoke control projects in shopping malls. I think we've. With my team we've delivered six or seven, very large shopping malls in In terms of design of the smoke control systems. now, uh, we do much less of that because we, uh, Specializing tunnels last years, but still were involved in some refurbishment projects off of modern walls. There's also not that many being built from scratch in Poland nowadays. So that also. The landscape has changed a bit, but still it's interesting projects. And, um, what I'm going to talk about today does not only cover the shopping mall, but it's also very relevant. If you there's a, in a railway station. Uh, airport any actually any mixed use, large volume. Uh, building where you would have a common smoke reservoir from which you would like to extract smoke. So okay. So that, that was an absurdly long introduction to the podcast episodes. So that's, let's jump into the knowledge that I wanted to share with you. So I've identified seven things. I would love to talk about, uh, when thinking Designing smoke control in a shopping Uh, let's say in a common mall, like a situation in which the fire is in some sort of compartment or directly within And the smoke is meant to, to fly into that mall and be extracted from it. So not a situation in which you would have a local smoke control in the shopping unit. And you would like to keep the smokiness in the shop. precisely opposite situation where you would like to release uh, the smoking to the mall and safely extracted from that place. That's very. Very possible. Uh, obviously. As much related to the size of the shop from which you do this extraction. That's probably the first thing to, to mention, like what kind of shops. You can, or what kind of compartments you can safely, Ventilate through a common space through a mall, and there are some guidelines. Some of them say 1300 square meters. Some guidelines say 900 square meters. I think, there is no really, um, single or volume of. What kind of compartment you can safely. Ventilate through a common space. It's difficult to get, to just give a number in square meters because there's always the problem. What if the thing is one square meter above about the dimension. And we always get into arguments with the investors and designers, like what happens in that situation? Well, As a common rule where you usually go with, eight, 900 square meters. The maximum, we are very comfortable with, extracting , through mall. The shape and length of the, um, compartment also matters a lot. So if the shape is complicated, it may be very difficult to actually extract Uh, we even defined a very robust, Definition of what it means that the shape is complicated. So you probably remember the old game Tetris. The blocks falling from this car and, disappearing when you, when you merge them. Uh, so if you can define the shape of a compartment with. One of the blocks. Original Tetris. It means the shape is quite simple. If you cannot stand it, it's complicated. And this rule of tamp has served Uh, very well deal. So, yeah, We know now what situations we're talking about, the compartment. That is being ventilated through a common space Now question, number one. Uh, or that you need to ask yourself why I'm doing What was the point of, of, of smoke control in this. Arrangement. I am I caring about life safety? Malls can be tricky, especially that, uh, I, I'm not sure how it's designing your countries, but in Poland you will usually have, some sort of food court area or a recreation areas on the. Upper levels of, of the mall. You would usually have, um, cinemas and stuff like that. And upper levels of the mall. Not, not really shops. So, so you'd have a situation where people would be less mobile. Maybe they will be sitting, eating. They would be probably quite busy and there's a good chance. There would be a lot of people in the top level of the mall. So life safety is not traveling there. You need to have a capacity to evacuate these people. You need to have a capacity to, alarm them about the fire. Especially the fire cannot cure far away from them and the steel can be affected by the smoke flowing through the mall. If you gather, read underneath the roof of the mall. So the people on the top level are usually the ones you worry about the most, if you're considering life safety. So that would be one, a very strong design goal. Another one would be to limit the extent of how far the smoke goes into the mall. So you, you reduce the damage, which. It's not about damage. I actually, I mean, if the shopping mall gets damaged, they will. Get money back from the insurer and it will be all right in the end. But it means parts of it will be closed. And, These sort of resiliency of the building. It's very important nowadays. You want to have business continuity? You want to be able to use the building It's supposed to be used as quickly after our fire as possible. So actually designing a very robust smoke control system is a way to, Provide that you will be able to start the operations. Uh, Back to normal quicker. If you have good smoke control, then if you have a best of, of control, if you have none, maybe your goal is to fulfill legislation. Then you have to ask yourself a question. Um, am I pursuing some better goals or I just want to be done with my system, maybe just a simple, robust calculation from NFPA 92 or some 12101-5 The European standard is just enough to, to get your thing. Past and maybe you don't help. Maybe you don't need to go into expensive. performance based engineering process for these Maybe all you need is just a simple system. And that, that, that may be a goal. And it's a very valuable many objects where we were involved with. that the smoke control would be designed for this particular purpose to tick a box where if you have smoke control, you can build a larger fire compartment that. Which is very attractive for four owners of, of, of, of the mall Maybe you have some complicated geometry, maybe you have underground levels where you have mall areas. Maybe you have some parts of the building that you cannot ventilate through. Large, a small reserve wars in the, in the mall itself. That also happens quite often in the projects we've So, so you all also have very significant challenges with life safety in these these places which would need your increased attention, but you need to understand that you cannot go into the project without understanding. What you are doing the project for, even if it's just to, to have one piece of smoke, exhaust, to tick a box, that's also a goal. And you also need to be aware of that because that will drive. Many of your design decisions. Second thing What firearm are you dealing with? That's not the very trivial question that actually quite difficult to answer. If I'm honest with you, we would usually go with some design fires. That are listed in 12101 part five, which can be traced back to BRE368 I think was the number. Written by Morgan ha. A magnificent piece of. Of fundamental literature for an export control engineer. I highly recommend. Reading that that's like 20, some years old, but still. Very interesting, thing to read and very comprehensive summary of the, of the knowledge in, in fire. But. You really need to understand how design fire will change your system. You're basically dimensioning against the fire. The size of the fire one and the word the fire is positioned. We're going to talk about architecture later in the episode, but the fire itself, if you have two and a half a megawatt, if you have five megawatts, if you have 10 megawatts. Three completely different fires, three completely different outcomes, three completely different fire plumes. You need to understand which. You have and why you've picked And. I something see, we, Jump into this design fire. Loopholes or something. We just pick one from the list without comprehending. Is it really possible in this particular setting? If you have a. Mole stand. Where they sell mattresses and you have a small shop where they sell cupcakes. It's obvious Fire threat in both of these places will be completely different. You have a bookstore is different. You have a jewelry shop is different. It's important to understand the consequences of each of those. However, you also must understand it. A mall is a living thing. The fact that today there's a jewelry shop in this particular corner of the shopping mall. It doesn't mean that there will not be a shop with mattresses in, in 10 years. And your smoke control will be as good as it is when you design it. So you need to have this in your mind that buildings live and change. You have to really focus and choosing. Really robust design fire. And I'm usually a fan of, of actually going into a little bigger. Uh, designed fires to really test my systems against them. And optimize them for that. And this usually in the years after we designed the shopping mall, now we have this experience because some We have originally designed, they would come back to us and. The people will be doing some changes in them. And they usually are very happy to find out that nothing must be done with the smoke control system, because it was designed with a. Really good design fires in mind. And what we've done many years ago already covers. The new scope of use. If you. Push for, uh, small fires. If you a common case would be someone considering, let's say a medium growth. Uh, Fire and having sprinklers and say that. Sprinklers activate after I dunno, 150 seconds. So there's design fire is cut down to 700 kilowatts or whatever the value would be at the point. Uh, and just go with that. That may not be sufficient if you want a robust system in future. So, yeah, choosing design fire. That's that's an art for sure. That's probably one or maybe many podcast episodes that need to be recorded on how to choose that. It's not simple, but it's the foundation of your design. Um, probably the most important, most impactful thing that you have in your mall. The second, most impactful thing would be architecture. There are so many architectural features of the mall. With the building that impact how the, how much smoke you will have to deal What's the threat in your building. It's actually a sounding to what extent? Architecture facts. That was something I wanted to, test in my PhD to take a deep look into in my, in my research. And I was astounded with the variety of outcomes. Achieved with the, just deferring the architecture, having the same fire. Pretty much, same mall, just playing with the balcony Uh, the distances, the size of the openings in the shopping fronts. All of this together has tremendously changed The resulting, uh, dimensioning of the systems that I was working with. I have one paper in English from my PhD. Not very much. I was not a very prolific. research or back then. Uh, probably today I would push much more papers out of, out of such research, but I just have one and I'll link that in the show notes. If you would like to look. Further deeper into. Into that research. Now when you consider architecture, there are some very impactful architectural details of the building. That would be a very strong drivers. Of the dimensioning of your smoke control and the performance of a smoke control. One would be balconies, projecting balconies of both for the mall. So the smoke must exit. Let's imagine a firing. Uh, in the shop. You have fire, the smoke is generated in the shop. Because you don't have individual smoke control in the shopping unit, the smoke must be extracted into the mall. So it will flow through an opening in the shopfront. And then it it will either fly undisturbed to the top of the mall, or it will fly underneath the balcony. And there's a lot of things happening when the smoke flies underneath the balcony. Imagine it has to change its flow direction, at least three times. So master changes direction when it exits the shop. So. It must flow through the doors underneath the downstairs. then it must flow or is only underneath the balcony and then it must flow vertically. To the up again. When it reaches the end of the balcony. So every, every time I smoke changes is the direction they Um, significant mixing of smoking. Surrounding air happening. And that leads to increase the amount of smoke that you have to extract. Every time smoke moves, you have more smoke. That's a, that's the thing with smoke control. That's the problematic thing with smoke control. Every time it moves, you have more of it to extract. And, uh, because you need a very, very little amount of soot or smoke smoke in, in, in To make it a obscure visibility in regular durability criteria. You cannot really dilute it to a point where it's not a threat anymore. So you always just end up with one more smoke. And what's worse. You end up with the smoke that is cold. So there's not much you can Do about it. If the smoke is cold, if it loses you have a problem because it's very difficult to drive it to places where you want it to be driven. Now. As the smoke moves. As you change the amount of the smoking smoke plumes uh, we reach. an interesting paradigm. That's an underlying paradigm of the design of smoke control that we have. How do you choose how much extraction do you need to remove that smoke? We assume that the smoke is being produced in the fire. We have our. Models be it axyssymmetric smoke plumes or spill plumes for malls. In which you can calculate the amount of smoke produce smoke as the mixture of the fire smoke and the entrained air that this mixed with it. You calculate how much mass is that? And you have an answer you assumed it's if you extract. As much smoke as you produce. You're good. That's that's a working system. So we use this part time to design our smoke control. We basically find the equilibrium. Between the amount of air extracted. And the amount of smoke produced In the system for extraction, you would have two possibilities. You can extract it with mechanical means. So with mechanical ventilators, Where. You basically have powered device that extracts. A certain volume of smoke is very important to understand that. Extraction fans are volumetric machines. they always removed the same volume. Which means they remove a varying mass of smoke because mom smoke has temperature. Temperature affects density. the mass flow. So you always remove the same volumetric capacity, but the massive mass flux. We'll we'll change in the power to ventilator. And you can use natural ventilators, which use the smoke buoyancy. To extract the smoke from the building outside. We extensively work with natural ventilators. as you maybe heard in episode, 50. we do a lot of wind engineering and wind engineering was largely related to natural smoke control. So how wind conditions affect the ventilators Oh, boy. We're. We're in troubling here. Uh, the way how we design natural ventilators is not very robust or, it doesn't really have huge physical meaning. Because of how industry is tweaked towards a very specific parameter of a single vent later called the discharge coefficient or, or dynamic three area. And this parameter is. In the end, very, very weak predictor of the performance of natural ventilator on a real building. But boy that that's a separate podcast episode and I promise I'll deliver that I can rant on that for hours. Promise. I will do that in the, in the, in the show. So you haven't leaders powered natural ones that extract a certain amount of, of, of smoke. And no how much smoke goes in there as mentioned axisymmetric blooms. Spill plumes star models. Uh, they usually correlate the amount of smoke. To the parameters of the fire. Either it's heat release rate or convective heat release and volume so-called mutual origin, Sarah, the In which, At triangle representing firewood starts underneath the ground. It's I'm really bad at describing that, but there exists such a thing as a virtual fire origin and it's used in many. Two models in some models, you just use the perimeter of There's also a valid approach. And, uh, from this. Pardon me, there's a fire. You have the first value of your mass flow. Then you usually rely on the height difference. Between the plane at which the fire is and the height at which you want your smoke layer to be. And there are some additional coefficients for the flow through openings floor flow underneath downstairs floor underneath balconies. That helps you approximate. The mass flow. That's in the end of your system. So many coefficients, many assumed to the. Variables. not that much science in that. So you must understand that this correlations are usually, best fits. To a certain set of experiments carried in the past. So what, what we have today are basically results of some experiments run in eighties. And scientists trying to fit. some sort of curve. To the results of this experiment and then translate it into some sort of empirical relation. That correlates to the amount of smoke to the Heights. On which diaries in training to the smoke plume so that's what we have. I'm not sure if these smalls are perfectly. If these models are really, uh, And, we usually can optimize much further than they are the analytical Mt. Models. With CFD with advanced tools. So. I highly recommend that item. I don't know how popular is that in your country, but here we would not do a project without CFD. Like it's just how We would always run You have these calculations for a mall? So it's, it's definitely a way that's very helpful to achieve. Hopefully my solutions. I highly recommend that if, if it's not being used in your country, Write I can help you find resources and learn how to do that. Maybe. We can change the mind of your country too. To approach her. Performance based engineering in smoke control. We were very lucky in Poland to have this written in our low. That we are allowed to do performance-based engineering. And since then it's been magical. We were able to really design our systems, not just, Or read the number from The fourth thing I wanted to talk about. I just said that the amount of smoking the smoke zoom would be result of the firing compartment and the flow out of that compartment. So let's, let's touch that. Let's touch the exits off the shopping. You need. So the shopping France and openings in that, and there was one of the. Most interesting and frustrating finding of my PhD. So that's the story. Um, Storytime. If you. Go the traditional way. You would like to let let's say you would not, you would like to optimize your system for costs for money. So you would like to end up with the smallest system you can have. As I said, we live in a paradigm where the mass of smoke, flowing into the smoke reservoir. Equals the mass of smoke extracted with your ventilators. So what's the optimisation goal there?. You want to have a slow mass of smoke flowing. As possible. Now you look at the equations And you may find it amount of mass exiting. The shop. Not in all methods, but in some of the methods. It's related to the size of the opening. So, if you make larger opening, you have more smoke. If you have smaller opening, you have not that much smoke. So a clever engineer would say, okay, let's do the opening to the smallest possible. This way we reduce the amount of smoke that. Is being extracted To the mall and thus we can design a smaller That's a very clever optimization based on the assumptions of the standards. Now I was testing this in my PhD. And they've very quickly realized. That this relation of the amount of smoke producing the in a compartment. To the size of the opening. It's not very valid. It doesn't hold infinitely. So you could assume that. The bigger, the opening, the bigger, the amount of smoke extracted rides, you know, What happens if you have a hundred meter long opening or 500 meter We have infinite amounts of smoke. Well, no, There's conservation of mass and energy in the fire that there's not enough energy producing the fire to move that much So actually it flattens out at some point where. No matter how much, how much bigger your opening is, you will not produce more smoke through that opening. It will just flow from the opening with a slower velocity. Essentially meaning there's less entrainment and in the end, if I could observe that in my PhD. And it was one of the main findings of that. Very interesting finding. Now I've also observed the second If you have a shopping unit. And the exit from that shop, the opening to the mall is very small. You basically trapped all the smoke inside that shopping union, creating a very Untenable conditions in that compartment very quickly. But if you really had to large opening. Especially if you had very tall opening. You could really release. Most of the smoke to the mall from which you can save the extracted. Maintaining stratification of the smoke layers inside the compartment. And providing conditions, insights that almost Conditions in, uh, ventilated compartments. Of course that holds for warm smoke. So if you have a. Very robust sprinkler system and it just extinguishes the firewall. Then you have no smokes. You win. there are things that I have not taken into account when doing my PhD. But still. If I used larger openings, I got better results. I got safer system. And not much bigger system in the end. But the safer system, contrary to what you would find just blindly following standards and making conclusions on how variables are inputs into analytical calculations. So this is also something I urge you to think out of the box and try to seek, um, Um, solutions that may not necessarily necessarily. B. Once directly resulting from the Next thing. fifth or maybe the sixth thing I've lost my count in here. It's the way, how you supply the makeup or into your shopping Boy. That is a challenge. I always say it's, putting more extraction in, um, in the shop. It's not a big problem. You just put one more ventilator on. the roof and you have more exhausts. It's usually very easy doable. It's just a matter of money and power. However to put more air into the. Mall. That's a huge challenge. And usually we have more problems with supplying care. And extracting Why is that we need. Uh, low velocity flows in the malls. As I mentioned the smoke I don't see, as long as it flies up, you can pick it up wherever you need to be. Get up and extract. If it's cold, it does not have brilliancy. It flows everywhere. It mixes everywhere. It stays. At the level that it mixed, you cannot do anything with such a You quickly lose visibility conditions in your mole. You have people exposed to smoke something you really do not want to do when designing smoke control So having a really good, robust air supply is critical. Now main question is with what the below city, there can be supplied into the mall. And boy, that's a challenge. Some guidelines would tell you one meter per second, some will tell to some will tell three. My experience is that two is already a lot to meet. A second is already a lot in the Already leads to problems with mixing the air and smoke layers in shopping malls. So I would definitely recommend below two. People don't recognize that that kinetic energy is when the power of two or velocity so. Having a little quicker areas, actually, you put much more. Kinetic energy. You put much stronger flow into your building. That must stop somewhere before it mixes with the smoke. So it's paramount to have. flow. Introduced to your. compartment as slow as possible. And that requires a lot of openings, which you usually don't have. The worst is when they tell you to compartmentalize your shopping mall into smaller fire compartments. And suddenly you may end up with. Part of the molded even doesn't have a connection to outside through external doors. That's horrible to work I usually try to avoid that at all costs. And I would prefer one giant fire compartment with a controllable air Rather than very high, the compartment flies, shopping mall with no way to introduce makeup, or it will be much worse. the large fire compartment. Contrary to what colleagues from fire department say, in my opinion, would be much, much safer building than, than one compartmentalize heavily from the perspective of life safety. Of course. Not from the maximum damage that the fire can do to the building. From that perspective, of course. Most likely compartment digitalization would. B. Or Maybe it would not, maybe, maybe you should apply risk methods. You've learned about them in the podcast. Another another clever use of risk. T to judge From no other better way to do that. So, so far from the things I wanted to share. We had the size of the compartment that we can safely, ventilate through a common mall we had choosing the goal of our smoke control. We had. Choosing the size of the fire and the impact of the design fire on the design of smoke control. We have talked about. How the architecture influences the flow of smoky weather to shape of the mall balcony Openings between the shopping mall levels. We called them voids. These are actually very important, how you shape them. How many is there? How big there are related to the size of the mall. How shopping fronts will influence that. How we calculate the mass fluxes in the shopping mall. And, how do we supply era the important aspects of designing smoke control, besides just choosing an extraction rate volume or locating your. Powers or natural bands on the roof. Many, many things that go into design. But now for a final thing. Let's say you've, you've done a great job. Let's say you've designed a really flawless smoke control system. How do you know that it's built to your expectations on the building? That's something. We also learned the hard way after designing many systems. Then having the ability to go to the mall. Do hot smoke desks. See how it performs and pick up so many. Uh, weak points. Sometimes in the design, I'm not claiming our design is always flawless. We're constantly learning and improving. It usually is quite good. I must say I'm probably both myself and my But we sometimes make mistakes. Of course. Most of the time that mistakes are on the somewhere between the design and execution. Maybe someone blocked the device incorrectly, maybe someone programmed the thing incorrectly. Maybe someone has mistaken that direction may be there should be a smoke curtain. And installed, but it's not there. Maybe it's just not operational. Maybe something is not powered. Maybe something is in maintenance mode. Maybe some of your smoke control damper has broken. They do that all the time. Uh, so there's so many tiny things that can affect the final performance of your system that needs to be checked before the building If you want to be sure that your building is delivered as you designed it. It must be tested in a verified. And from my own experience and the experience of my team, no, by the way, then hot smoke tests. I've had a podcast episode about that with, some Polish colleagues. Piotr Smardz and Janusz Paliszek check from INBEPO company in Poland. As ITB, we also do these tests. I think at this point we've done. Something like 13 hundreds. Yeah, individual hotspot tests in more than 150 buildings. So is a pretty decent, body of experience of testing real buildings. Colleagues from endeavor also have done them in hundreds. So a collective experience or from two very, um, experienced bodies in Poland The drum, these tests and they We run this test, not for the purpose of verifying if smoke flows upwards, and if smoke extraction really works, but we do this in particular to check how the automation of the building reacts to a fire. Is it as we expected it to be, uh, it's very important that it usually is not unfortunately, but this husband, this approach really allows you to pick this errors. And fix them. That's the most important thing you can fix them. Very easy. And in the episode, About hotspot test, which I link in the show notes. You can learn all about it. If you have not heard that episode, Really great. Follow-up through this episode. So you go down important things that go into design of more smoke control system. I hope you've enjoyed This, this list of stuff to consider. I'm gonna say in recent discussions with some colleagues. I rarely see these things being discussed. I very rarely hear. Discussion about the impact of architecture or the makeup or strategy. Or the way how you shaped the shopping front on a behavior of smoke control in the mall. People usually focus on how much. extraction how much cubic feet per minute. As my colleagues in the us like to. Uh, measure the headset. You have to extract you have a system and age with just stroll numbers over numbers. And of course it's important. It's a factor in the design. It's the defining factor of how much money we'll spend on that installation. But it can be smart about if you can touch some other aspects of your building, like the architecture, maybe you can put a smoke curtain somewhere that will direct smoke in a, into a better path. Maybe you can reduce The threat by defining what types of shops can be placed in a certain location of the mall. And that is, imposed in the building. Guidance book and will be maintained through the life of the building. That's a pretty decent way to reduce the design fire and make sure that actually the design fire is applicable for whatever happens with the building in the future. There are many, many clever ways in which you can, uh, alter the smoke control of a mall or large space as mentioned. Airport railway station and the large volume building. And, I've also see my colleagues, scientists who. pursue scientific, uh, research on this topic who very rarely see these minuscule details. And, yeah, if. Very urge them to, to. Think about this more holistically, w what are the factors that really make or break a smoke control system? Because sometimes they are not the things that come to mind first. So that's Uh, for today's episodes myself ranting on. Smoke control of malls, uh, presenting you my state of mind from many, many years ago. plugging in some PhD I've very rarely talked about this in public, actually that I've done this research. Most of this research. Before my career became sort of international. So you may never heard about this, this research sort of greater place for you to have hear about this for the first time. as I said, I wrote a memo to myself that maybe I should write a book about this. Maybe I actually should. It could Nice. Nice guidebook. There are resources available. And to be honest with you, I now prefer talking, not writing. So. Here's my best. Try on. How to deliver an efficient, smoke control animals. Let me know what you think. Let me know how you deal with a small controlling in large volume. Volume buildings in your countries. Maybe there are things you care about that I have not mentioned in here. I would love to hear your perspective and learn from you. Maybe improve my own knowledge. On how smoke control systems can be delivered. I hope some of this was useful. If you're a smoke control engineer, I guess it was, if you're not a smoke control engineer, I think we've touched many interesting points on what, uh, makes. Fire be a threat. And, um, what makes smoke, behaving a certain Hopefully that this also useful to you. And yeah, that, that would be it. Thank you very much for spending this time with me And I hope to see you back in the podcast and next week. Take care. Bye.